Xiss, now bereft of a Master, joined the "Padawan Pack," a group of Jedi apprentices whose Masters had been killed over the course of the war. A year after the genocide on Ohma-D'un, the Padawan Pack was dispatched to the embattled world of Jabiim to fight there on the Republic's behalf. Command of the Republic army on Jabiim fell to Xiss and her fellow orphaned Padawans, as all higher ranking Jedi eventually fell to the Jabiimi Nationalists, a pro-Confederacy political movement that wished to secede Jabiim from the Republic. After weeks of fighting, the Padawan Pack pulled their forces back to Cobalt Station, where they were assaulted by the army of Alto Stratus, the leader of the Jabiimi Nationalists. The conflict at Cobalt Station lasted for several days, and Xiss gradually began to slip to the dark side of the Force, becoming more and more brutal on the battlefield. On the forty-first day of the Battle of Jabiim, Zule Xiss was crushed to death by a damaged Republic AT-AT while attacking enemy forces. Except for Anakin Skywalker, every other member of the Pack was killed by the end of the battle, and the Republic was forced off the world only days later. The surviving Republic forces fled to New Holstice, where Skywalker added Xiss's name to a memorial for fallen Jedi.

Xiss and the Republic forces soon came upon a massacre, discovering that every Gungan in the colony had been killed. The Jedi engaged several Confederate battle droids that were examining the Gungan bodies, concluding that the massacre was not the work of spice miners. The true culprit, the Confederacy's Gen'Daibounty hunterDurge, soon revealed himself and confronted the Republic force. During the ensuing melee, Xiss was able to stab Durge directly in the abdomen; however, the wound did not kill him, as his Gen'Dai physiology allowed him to sustain heavy wounds and remain standing. Durge struck Xiss across the face, rendering her unconscious while Glaive attacked the bounty hunter. An overwhelmed Durge called for reinforcements in the form of super battle droids bringing the swamp gas that had killed the Gungans. While Kenobi and Glaive struggled with the gas and Skywalker and Alpha searched for hostages that had been taken by Durge, the Gen'Dai bounty hunter found Xiss's unconscious body and lifted it off the ground. Glaive attempted to mind trick Durge into releasing her, but she was instead saved by Kenobi, who attacked the bounty hunter from behind. Glaive was killed shortly after in a surprise attack from the Dark AcolyteAsajj Ventress, Durge's compatriot and the Separatist commander behind the genocide of the Gungans.[3]

Durge and Ventress nearly killed Kenobi, but the Jedi Knight was saved by a revived Xiss when she drove her lightsaber into Durge's back. However, Durge's lack of a central nervous system allowed him to continue fighting, as he explained while tackling Xiss. He smothered the young Falleen and began cutting her face with a large blade, but before Durge could kill her, Xiss grabbed the blasters from his holsters and shot him in the chest. As she rejoined Kenobi, Durge left to hunt down Alpha and Skywalker while Ventress remained to finish off Kenobi and Xiss. Using the dark side, Ventress reanimated many of the dead Gungans in order to keep the two Jedi off-balance during the fight. Xiss recovered her lightsaber that she had lost while fighting Durge; however, before she could use it against Ventress, the Dark Acolyte cleaved off her left arm. Weakened by the poison gas and wounded by Ventress, Xiss was nearly killed before Skywalker and Alpha returned to aid her and Kenobi. Outnumbered, Ventress and Durge abandoned their mission and fled Ohma-D'un. Xiss accompanied Alpha as he carried Glaive's body onto their LAAT/i alongside Kenobi and Skywalker. The group then left the moon to warn the Jedi Order about the new swamp gas weapon threat.[5]

Xiss once again fought alongside Alpha-17, Anakin Skywalker, and Obi-Wan Kenobi, as Kenobi had been assigned as theater commander for the Jabiim conflict. By the thirtieth day of battle, eighteen Jedi and nine thousand clones had been killed. Kenobi and Jedi GeneralSirrus were presumed to be among the dead, adding Skywalker and Sirrus's apprentice, Aubrie Wyn, to the Padawan Pack. GeneralLeska, now the highest-ranking Jedi on Jabiim, ordered the Padawan Pack to avoid the front lines and protect a supply convoy headed toward Cobalt Station, as she refused to send more Padawans to their deaths. While guarding a convoy of All Terrain Experimental Transports and All Terrain Tactical Enforcers, the Padawans were attacked by Stratus's droid forces. Xiss followed Skywalker and several other members of the Pack into battle against the droids while Wyn and Nend remained with the convoy. Knowing that the battle droids were single-minded, the Padawans distracted them with an obvious target before launching a successful ambush. The tactic, which had been developed by Skywalker and his Master, repelled the droids and allowed the Padawans to get the convoy moving once more. Despite the victory, Xiss remained pessimistic of the situation, citing that even the most advanced Padawan, Mak Lotor, was inexperienced in war. Later, Windo Nend attempted to make conversation with Xiss, but she quickly became annoyed and threatened the Aqualish. Vaabesh explained to Nend that she was only defensive as a result of the loss of her Master on Ohma-Du'n, whom Vaabesh believed to have truly taught Xiss what it meant to be a Jedi.[4]

On day thirty-four of the battle, the convoy protected by the Padawan Pack walked directly into a minefield set up by Alto Stratus's Nimbus commandos. Unable to safely navigate the field, the trapped convoy was quickly attacked by Stratus's forces. Although Kass Tod ordered that the convoy remain stationary in order to avoid the mines, Xiss and Skywalker insisted that they fight back against their attackers. After Mak Lotor passed out from overexerting himself in the Force while remotely detonating several mines, Xiss aided him in moving to cover. The Jabiimi Nationalists soon retreated, allowing the convoy to continue on to Cobalt Station.[4] Once there, while enjoying a brief break in the rain, Xiss and the Padawans witnessed Confederate reinforcements landing on the planet. During a communication with Orliss Gillmunn, the Padawans were informed that General Leska had gone missing and that they were now the highest ranking members of the Grand Army of the Republic on Jabiim. Cobalt Station was the last remaining Republic fortification on the planet, and it stood between Stratus's approaching forces and Monsoon Mesa, the evacuation site for the remaining Jabiimi Loyalists and clone troopers.[1]

Zule Xiss, moments before her death

Despite their likelihood of defeat, all of the Padawans agreed to remain at Cobalt Station in order to buy time for the escaping Republic forces. Xiss was initially reluctant to commit herself to what would be an almost certain death, but ultimately decided to stay and fight. While preparing for Stratus's assault, she armed herself with a DC-15S. The Confederates eventually attacked and found the defense of Cobalt Station to be far stronger than they had anticipated. Xiss spent time in the station's trenches with Windo Nend, encouraging her allies to push their attacks. On the second day of the assault, Xiss was running about the battlefront, using both blaster rifle and lightsaber to assail her enemies. By this point, her aggression had begun to worry her fellow Padawans, with Mak Lotor going so far as to say that she was falling to the dark side.[1]

Embracing the anger that her Masters had long warned against, Xiss was able to kill many members of the Nimbus Commandos. Fighting in the shadow of one of the Republic's few remaining AT-AT walkers, Xiss maimed a Nimbus and prepared to execute him. However, before she could, the AT-AT was hit by heavy fire and fell to the ground, crushing Xiss and the commando.[1]

The Battle of Jabiim ended two days later with the death of Alto Stratus at the hands of Aubrie Wyn. Despite Stratus's death, all of the Republic forces at Cobalt Station were killed, including the remaining members of the Padawan Pack.[1] Anakin Skywalker, who had been recalled from the battlefront days earlier, arrived at Monsoon Mesa to oversee the evacuation of the surviving Republic forces there. Despite the pleas of the Jabiimi Loyalists looking to flee their home and reprisals from the Nationalists, Skywalker chose to evacuate only the Republic's clone troopers, as the number of transports was limited. Having earned the hatred of Orliss Gilmunn and the Jambiimi despite the Padawans' efforts to protect them, Skywalker and the clone forces pulled off the planet and headed for the Republic hospital world of New Holstice.[7]

On New Holstice, Skywalker was shown a monument for fallen Jedi built by the planet's natives. Skywalker added the names of his fallen comrades to the monument, including Zule Xiss, by whispering their names into memory moths which would in turn be whispered by the wings of the moth for eternity.[7] The struggles and failure of Xiss and the Padawan Pack on Jabiim were later covered up by Supreme ChancellorPalpatine's administration in an effort to keep negative news of the warfront from reaching the public.[8]

Zule Xiss was an abrasive Padawan, quick to anger and often demeaning to others.[3] Her attitude problems led her to be passed from Master to Master in her early career until she was placed under the instruction of Glaive.[4] Glaive, who was similarly abrasive, served as her final Master up until the mission to Ohma-Du'n. During the briefing for the mission, Xiss expressed her skepticism of the combat abilities of Gungans, claiming that they would be no match for spice miners with a vendetta. The Padawan also thought little of clone troopers and was surprised when Alpha-17 rebuked her, as she was under the impression that clones lacked independent thought.[3] When Glaive was killed by Ventress, Xiss continued to fight in his honor, claiming that she and Kenobi would kill Durge and the Dark Jedi for her Master's sake.[5]

Xiss's reverence for her late Master faded quickly in the wake of Ohma-Du'n, however. Xiss grew colder and less tolerant of others, and by the time of her tour of duty on Jabiim, the young Falleen was completely distanced from her peers. She refused to make conversation and had a highly pessimistic outlook on the abilities of the Padawan Pack. When Windo Nend attempted to interact with Xiss, he was met with threats and irritation. As Vaabesh attempted to rationalize her anger by claiming that her difficult apprenticeship and the loss of her Master led her to act out, Xiss denied Glaive's influence on her. She claimed that she hated the man and often wished she had killed him herself.[4]

When it came time to decide whether or not to abandon Cobalt Station or to stay and fight to the death, Xiss was the only Padawan hesitant to stay. She eventually relented, however, glad that her death would now be on the battlefield instead of in a cantina brawl. As the battle wore on day after day, the jaded Xiss slid toward the dark side, embracing her aggressive nature and using it to her advantage while battling the Confederate forces. At least one member of the Nimbus Commandos referred to her as a monster after witnessing her brutality. Despite her resentment of both her allies and enemies, Xiss wished the best for her comrades in the final moments before her death.[1]

Xiss behaved unlike most members of her species,[9] openly displaying raw emotions to others and maintaining a constant shade of red in her skin pigmentation. She commonly wore sleeveless robes and carried a green-bladed lightsaber.[4]

"I haven't been trained to use any of this…""Neither have I. Just rely on instinct."

―Elora Sund and Zule Xiss on using weapons other than a lightsaber[src]

Xiss, now with only one arm, joins the fight against Ventress on Ohma-D'un.

As a Jedi Padawan, Xiss was trained in both the usage of a lightsaber and of the Force. On Ohma-Du'n, Xiss dueled both Ventress and Durge and was able to land surprise blows on the latter several times—an impressive feat, given the bounty hunter's Gen'Dai physiology and skill.[3] Xiss was not as successful in her battles with Ventress, as the Dark Acolyte was able to cut of the Padawan's arm before the two even engaged one another. Despite the beating Xiss received from Durge, the amputation at the hands of Ventress, and the effects of the swamp gas she had inhaled, Xiss remained determined to survive, picking up her lightsaber once more and joining Kenobi, Skywalker, and Alpha in their advance on Ventress.[5]

On Jabiim, Xiss fought for days with little rest in unforgiving environments. Although she had only been trained to use a lightsaber, the Falleen took up a blaster rifle while defending Cobalt Station. As she began to slip toward the dark side of the Force, Xiss used her hatred and anger to fuel her aggression on the battlefield. In her final battle, Xiss took up her lightsaber once more, and her brutality inspired fear in her enemies.[1]

The script of The New Face of War identifies Xiss as a Falleen, despite her appearance indicating otherwise. Xiss lacks many characteristics commonly found on Falleen, including green skin, scales, clawed hands and feet, and prominent ridges on the face and spine.[9] While the red color of her skin can be attributed to the natural ability of a Falleen to alter skin pigmentation from green to red, some have interpreted her species to be Zeltron, as her appearance matches theirs much more closely. When questioned on this topic, Lucasfilm official Leland Chee confirmed that Xiss was indeed a Falleen.[2]